"It means the third rail has seven hundred volts of direct current running through it," Fang said.

James Patterson -- The Angel Experiment

And of course Edison urged the fair to use direct current, DC, the prevailing standard.

Erik Larson -- The Devil in the White City

On one side was General Electric Company, which had been created when J. P. Morgan took over Edison’s company and merged it with several others and which now proposed to install a direct current system to light the fair.